Geoscience Issues Research Articles

Permafrost and Gas Hydrate Response to Ground Warming

This Special Issue of Geosciences is a collection of fifteen original research and overview papers on the response of permafrost and gas hydrates to ground warming caused by natural climate trends and industrial loads [...]

Discrimination and mapping ground surface freeze and thaw states over Northeastern China based on the improved dual-index algorithm

Accurate delineation of spatiotemporal variations in ground surface soil freeze and thaw (F/T) states is essential to appraise many geoscience issues, such as the hydrological circulation and land surface-atmosphere feedbacks. Recently, an Improved Dual-index algorithm (DIA) method was proposed by accounting for the influence of soil moisture variations on the discrimination accuracy with passive microwave remote sensing (RS) data products. Compared with the original DIA, the Improved DIA method has proven to be a more practical approach on surface soil F/T states discrimination. However, the method has only been applied and verified in cold regions of high-altitude (e.g., Tibetan Plateau), it's applicability and effectiveness in the cold areas in mid-high latitudes, where the geographic and climatic conditions are quite different, yet remained to be further explored. The present study investigated the feasibility of using AMSR-E (the Advanced Microwave Scanning Radiometer-EOS) and AMSR2 (the second Advance Microwave Scanning Radiometer) passive microwave RS data products to discriminate the F/T states of the ground surface for a long period from 2002 to 2019 by means of the Improved DIA method over a typical mid-high latitude cold region of Northeastern China. Seasonal variation characteristics of soil moisture in mid-high latitude areas were similar with those in high-altitude areas, even though the spatial heterogeneity of soil water content was significant in different regions. Discriminating surface soil F/T states with the Improved DIA method derived overall discriminating accuracy of about 91.6% in the study area, which demonstrated excellent feasibility of the Improved DIA method in mid-high latitude cold regions. The mapping results shown surface soil F/T cycle in Northeastern China responding to climate change was examined from the perspective of regional average, both the proportion of frozen soil area and frozen days showed significant decreasing trends continuously with differed quite spatially. The discriminating accuracy of the Improved DIA method was found to be lower in plain areas with dense populations and large farmland areas compared to mountainous areas when human activities were not taken into consideration, as quantifying human activities can be challenging. The Improved DIA method has been well verified in both high-altitude and high-latitude regions; it has great potential in global scale research.

A review of the 19th International Symposium on geodynamics and earth tide, Wuhan 2021

Modern geodetic technologies such as high-precision ground gravity measurements, satellite gravity measurements, the global navigation satellite system, remote sensing methods, etc. provide rich observation data for monitoring various geodynamic processes of the global Earth and its surface. The 19th International Symposium on Geodynamics and Earth Tides brought together scientific researchers from 26 countries around the world, shared the application of various measurements in different geoscience issues, covering Earth tidal deformation, oceanic and atmospheric loading effects, earthquake cycle, hydrology, Earth rotation changes, etc., and provided a precious exchange platform for global peers.

A Special Issue of Geosciences: Cutting Edge Earth Sciences—Three Decades of Cosmogenic Nuclides

What we know is a drop, what we don’t know is an ocean [...]

Gas Emission and Formation of Craters in the Arctic Permafrost Synopsis

This Special Issue of Geosciences is a collection of twelve research and overview papers devoted to shallow Arctic permafrost as a natural reservoir that stores large amounts of bound gas, mainly methane [...]

A molecular dynamics investigation of La3+ and Lu3+-ligand speciation in aqueous solution

Ion-pair association of rare earth elements (REE) with ligands is important for its mobilization, enrichment, and fractionation during hydrothermal transport process, which is of great significance to study REE ore genesis, weathering process, the origin and evolution of earth and other related geoscience issues. However, reliable experimental data are limited to a specific system or ambient conditions, which hampered our understanding of the geochemical behavior of REE. In the present study, classical molecular dynamics simulations were carried out to calculate the potential of mean force (PMF) between La3+/Lu3+ and ligands of Cl−, F−, OH−, HCO3−, CO32− and SO42− in dilute aqueous solutions from ambient to supercritical thermodynamic conditions. Stability constants were calculated from the PMFs and compared with literature reported and thermodynamic calculated data. The analyses of the PMFs and stability constants suggest smaller or highly charged ions are easier to form stable complexes. For both La3+ and Lu3+ containing systems, the stability of ion pair decreases in the order of CO32− > OH− > SO42− > F− > HCO3− > Cl−. The smaller Lu3+ is to form more stable aqueous complexes at all thermodynamic conditions and these stability difference may lead to significant fractionation between La (light) and Lu (heavy). The trends of PMFs calculated stability constants are consistent with thermodynamic calculated values and provide association constants of ligands for which no experimental data exist.

Evaluation of DEM interpolation techniques for characterizing terrain roughness

The emergence of modern geospatial techniques has brought a considerable change in data capturing, processing, and visualization tools. Digital elevation models (DEMs) are a 3D mathematical representation of the earth’s surface. Due to enormous advancement in geographic information system (GIS) tools and technologies, DEMs have a wide range of applications in natural resources management, environmental science, and engineering. In general, primary topographic variables extracted from DEMs are frequently less useful than secondary ones, e.g., surface roughness. Therefore, the precise values of secondary terrain features need to be derived from base DEMs. Generally, topographic roughness is an essential geomorphological variable that is a vital issue in geoscience. This research presents a comparison of deterministic interpolation methods, inverse distance weighted (IDW) and a natural neighbor (NN), with geostatistical technique, ordinary kriging (OK), to investigate the influence of generated DEM on quantifying terrain roughness relied on synthetic data and applying the zonal statistics tool. At the same time, a quantitative and qualitative approach is adopted to assessing the results through statistical methods and visual representations. The findings indicated that roughness values' behavior is broadly related to the quality of the built DEM. The NN approach yielded the greatest DEM accuracy, standard deviation, from a quantitative perspective (±0.930 m) than IDW (±3.748 m) and OK (SD = ±5.544 m) methods.

Changing roles of State Geological Surveys in the USA: experiences from Illinois

Abstract State Geological Surveys (SGSs) in the USA play vitally important roles, providing sound, unbiased scientific information to each state and the nation. Although implementation of each survey's scientific programme has evolved differently, these organizations are often the principal drivers of economic development, and they consult on policies for protecting land and water, mitigating geologic hazards and promoting sustainable development. The SGSs are represented by the American Association of State Geologists. For more than 110 years, they have partnered with the federal government on important geoscience issues concerning topographic and geologic mapping, water, mineral and energy resources, and geologic hazards. These collaborations continue to develop and expand across multiple specialties, providing critical support to the SGSs. The future role of SGSs will depend on legislative decisions, contributions to research and development and scientific advancement, and ability to leverage support from existing and new collaborations with academia and with federal, state, county and municipal agencies. The Illinois State Geological Survey, one of the largest SGSs, has continually pursued relationships across geoscience sectors to develop a strong multidisciplinary scientific programme. Going forward, all SGSs will be challenged to develop an effective data stewardship programme to communicate with a diverse clientele.

Remote Sensing and Historical Morphodynamics of Alluvial Plains. The 1909 Indus Flood and the City of Dera Ghazi Khan (Province of Punjab, Pakistan)

This paper explores the historical inundation of the city of Dera Ghazi Kkan (Punjab, Pakistan) in 1909. The rich documentation about this episode available—including historic news reports, books and maps—is used to reconstruct the historical dynamics between an urban settlement and the river morphodynamics in the Indus alluvial plain. Map and document-based historical regressive analysis is complemented with the examination of images obtained through different Remote Sensing techniques, including the use of new algorithms specifically developed for the study of topography and seasonal water availability which make possible to assess long-term changes in the Indus River basin. This case of study provides an opportunity to examine: (1) how historical hydrological dynamics are reflected in RS produced images; (2) the implications of river morphodynamics in the interpretation of settlement patterning; and (3) the documented socio-political responses to such geomorphological change. The results of this analysis are used to consider the long-term dynamics that have influenced the archaeo/cultural landscapes of the Indus River basin. This assessment provides critical insights for: (1) understanding aspects of the formation, preservation of representation of the archaeological record; (2) identifying traces of morphodynamics and their possible impact over the cultural heritage; and (3) offering insights into the role that recent historical documents can have in the interpretation of RS materials. This paper should be read in conjunction with the paper by Cameron Petrie et al. in the same issue of Geosciences, which explores the Survey of India 1” to 1-mile map series and outlines methods for using these historical maps for research on historical landscapes and settlement distribution.

Mapping Archaeology While Mapping an Empire: Using Historical Maps to Reconstruct Ancient Settlement Landscapes in Modern India and Pakistan

A range of data sources are now used to support the process of archaeological prospection, including remote sensed imagery, spy satellite photographs and aerial photographs. This paper advocates the value and importance of a hitherto under-utilised historical mapping resource—the Survey of India 1” to 1-mile map series, which was based on surveys started in the mid–late nineteenth century, and published progressively from the early twentieth century AD. These maps present a systematic documentation of the topography of the British dominions in the South Asian Subcontinent. Incidentally, they also documented the locations, the height and area of thousands of elevated mounds that were visible in the landscape at the time that the surveys were carried out, but have typically since been either damaged or destroyed by the expansion of irrigation agriculture and urbanism. Subsequent reanalysis has revealed that many of these mounds were actually the remains of ancient settlements. The digitisation and analysis of these historic maps thus creates a unique opportunity for gaining insight into the landscape archaeology of South Asia. This paper reviews the context within which these historical maps were created, presents a method for georeferencing them, and reviews the symbology that was used to represent elevated mound features that have the potential to be archaeological sites. This paper should be read in conjunction with the paper by Arnau Garcia et al. in the same issue of Geosciences, which implements a research programme combining historical maps and a range of remote sensing approaches to reconstruct historical landscape dynamics in the Indus River Basin.

A Special Issue of Geosciences: Groundwater Pollution

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Volcanic Plumes: Impacts on the Atmosphere and Insights into Volcanic Processes

Here we introduce a Special Issue of Geosciences focused on the scientific research field of ‘Volcanic Plumes: Impacts on the atmosphere and insights into volcanic processes’ [...]

Imaging the Pore Structure of Geological Materials with Bifunctional Nanoparticles.

Analysis of complex pore structure of geomaterials is a fundamental issue in geoscience. Here bifunctional nanoparticles with magnetic and fluorescent properties are introduced as novel markers for optical imaging of pore structure in geomaterials. Using the paramagnetic property, powder of the nanoparticle is driven into pores under an external magnetic field, avoiding a tedious sample preparation and eliminating artificial damage of sample preparation in conventional methods. Meanwhile, the fluorescent nanoparticle marker offers a sharp contrast imaging between the rock matrix (black) and pores (bright) under microscopy. Furthermore, fluorescent nanoparticles with different sizes and colors are designed to demonstrate the potential of the method for describing pore throat sizes. Combining the merits of the paramagnetic and fluorescent properties of nanoparticles, a convenient and practical sample preparation is proposed to promote optical imaging analysis of the pore structure in geomaterials.

Geoethics: Ethical, Social and Cultural Implications in Geosciences

Humans are recognized as a “geological force”, capable of modifying natural environments, and in virtue of this prerogative they have an ethical responsibility towards the planet. Indeed, studying and managing the Earth system, exploiting its geo-resources, intervening in natural processes are actions that involve great responsibilities towards society and the environment, of which perhaps we, as geoscientists, are not sufficiently aware. Only by increasing the awareness of this responsibility, can we work with wisdom and foresight, and respect the balances that exist in nature while guaranteeing a sustainable development for future generations. In order to define acceptable solutions to current global challenges, we need to take into proper consideration the ethical and social aspects involved in geoscience issues. Geoethics was born to define a conceptual substratum of categories, useful as framework of reference for geoscientists, to help them develop a new way of thinking and interacting with the Earth system. Geoethics widens the cultural horizon of geoscience knowledge and contributes to orient scientists and society in the choices for responsible behavior towards the planet. The paper provides an overview of the emerging field of geoethics, focusing on theoretical and practical aspects, by showing the trajectory that has led to the current point of development of geoethics and suggesting some cues for thought for further advancements of ethical thinking in geosciences.

Elastic Spatial Query Processing in OpenStack Cloud Computing Environment for Time-Constraint Data Analysis

Geospatial big data analysis (GBDA) is extremely significant for time-constraint applications such as disaster response. However, the time-constraint analysis is not yet a trivial task in the cloud computing environment. Spatial query processing (SQP) is typical computation-intensive and indispensable for GBDA, and the spatial range query, join query, and the nearest neighbor query algorithms are not scalable without using MapReduce-liked frameworks. Parallel SQP algorithms (PSQPAs) are trapped in screw-processing, which is a known issue in Geoscience. To satisfy time-constrained GBDA, we propose an elastic SQP approach in this paper. First, Spark is used to implement PSQPAs. Second, Kubernetes-managed Core Operation System (CoreOS) clusters provide self-healing Docker containers for running Spark clusters in the cloud. Spark-based PSQPAs are submitted to Docker containers, where Spark master instances reside. Finally, the horizontal pod auto-scaler (HPA) would scale-out and scale-in Docker containers for supporting on-demand computing resources. Combined with an auto-scaling group of virtual instances, HPA helps to find each of the five nearest neighbors for 46,139,532 query objects from 834,158 spatial data objects in less than 300 s. The experiments conducted on an OpenStack cloud demonstrate that auto-scaling containers can satisfy time-constraint GBDA in clouds.

Partial Randomness Hashing for Large-Scale Remote Sensing Image Retrieval

With the rapid progress of satellite and aerial vehicle technologies, large-scale remote sensing (RS) image retrieval has recently become an important research issue in geosciences. Hashing-based searching approaches have been widely employed in content-based image retrieval tasks. However, most hash schemes compromise between learning efficiency and retrieval accuracy, and can thus barely satisfy the precise requirements in RS data analysis. To address these shortcomings, we introduce a partial randomness scheme for learning hash functions, which is referred to as partial randomness hashing (PRH). Specifically, for constructing hash functions, a part of model parameter values are randomly generated and the remaining ones are trained based on RS images. The randomness enables an efficient hash function construction and the trained model parameters encode characteristics from RS images. The coplay between random and trained model parameters results in both efficient and effective learning scheme for constructing hash functions. Experiments on two large public RS image data sets have shown that our PRH method outperforms state of the arts in terms of both learning efficiency and retrieval accuracy.

Introduction to the Special Issue on Climate Change and Geosciences

With increasing interdisciplinarity, more studies are examining environmental problems from an integrated perspective. This is apparent in the geological sciences and physical geography, which incorporate various disciplinary approaches, including biology, pedology, hydrology, geomorphology, and climatology. This Special Issue of Geosciences is comprised of studies relevant to the biosphere, atmosphere, and hydrosphere, with terrestrial systems also considered. This Issue takes a geoscience perspective, embracing both geology (Earth science) and physical geography.[...]

A Tool for Classification and Regression Using Random Forest Methodology: Applications to Landslide Susceptibility Mapping and Soil Thickness Modeling

Classification and regression problems are a central issue in geosciences. In this paper, we present Classification and Regression Treebagger (ClaReT), a tool for classification and regression based on the random forest (RF) technique. ClaReT is developed in Matlab and has a simple graphic user interface (GUI) that simplifies the model implementation process, allows the standardization of the method, and makes the classification and regression process reproducible. This tool performs automatically the feature selection based on a quantitative criterion and allows testing a large number of explanatory variables. First, it ranks and displays the parameter importance; then, it selects the optimal configuration of explanatory variables; finally, it performs the classification or regression for an entire dataset. It can also provide an evaluation of the results in terms of misclassification error or root mean squared error. We tested the applicability of ClaReT in two case studies. In the first one, we used ClaReT in classification mode to identify the better subset of landslide conditioning variables (LCVs) and to obtain a landslide susceptibility map (LSM) of the Arno river basin (Italy). In the second case study, we used ClaReT in regression mode to produce a soil thickness map of the Terzona catchment, a small sub-basin of the Arno river basin. In both cases, we performed a validation of the results and a comparison with other state-of-the-art techniques. We found that ClaReT produced better results, with a more straightforward and easy application and could be used as a valuable tool to assess the importance of the variables involved in the modeling.

A Special Issue of Geosciences: Mapping and Assessing Natural Disasters Using Geospatial Technologies

Natural disasters, including floods, wildfires, volcanic eruptions, earthquakes, tsunamis, tropical storms, droughts, and landslides, can cause major losses of human lives and livelihoods, the destruction of economic and social infrastructure, as well as environmental damages.[...]

Geoscience Education in an Irish Context: A Need for Research

Perception and understanding of geoscience in Ireland by non-geoscientists have not been studied in depth, and an improvement in understanding how geoscience is perceived and engaged with will have significant impact on Ireland’s ability to meet a range of challenges, including hotly debated geoscience issues such as fossil fuel dependency, raw mineral management, water security, and shale gas extraction (particularly fracking). Geoscience plays an important role in society, and the understanding of geoscience of an average Irish person will be based on formal education (at primary and secondary level) and informal education through public outreach and news media. Geoscience is expanding in formal education and informal education is increasingly delivered online. Geoscience education in Ireland has not been studied in detail, and a better understanding of the state of geoscience education could improve connections between geoscientists and non-geoscientists. This paper discusses the scope of potential research into geoscience education in Ireland that could and should be undertaken in order to best understand and describe the state of geoscience education, and geoscience in society. Mixed-method research should be undertaken to study geoscience education at multiple levels and targeting multiple publics. This research into the state of geoscience education in Ireland would be valuable, to geoscientists and educators.